"This is a historical incident and use of a school email was not intended and is obviously extremely regretted."
The board has not met to discuss any decisions on possible disciplinary action or if the principal's computer would be further investigated.
The principal did not return calls from the Herald on Sunday.
He is the second principal of a New Zealand school caught up in the hacked Ashley Madison data.
Last weekend, we revealed that the estimated 22,000 Kiwi addresses, part of global data dumped by hackers, contained email addresses linked to 65 New Zealand schools — including a primary school principal who said he had never used the service and had no idea how his work account had been entered.
Authentication is not required to open an Ashley Madison account, and the legitimacy of some accounts on the site has been called into question.
Last week, New Zealand School Trustees Association president Lorraine Kerr called for schools to investigate staff whose work emails appear in the data drop, and the Ministry of Education has also called on school boards to act.